quick mathSolver

gistfile1.java

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;

public class Main {
  public static void main(String[] args) {
    	String input = "Here is $$$someVar=4,other=5:other+someVar*other$$$, and here is $$$someVar=4,b=5:someVar+someVar*6$$$, and lastly with no variables is $$$1+2$$$.";

        // Regex pattern to match substrings surrounded by $$$
        String regex = "\\$\\$\\$(.*?)\\$\\$\\$";

        // Compile the pattern
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(input);

        // List to hold the extracted substrings
        List<String> extractedEquations = new ArrayList<>();

        // Find matches
        while (matcher.find()) {
            extractedEquations.add(matcher.group(1)); // Group 1 is the content between $$$
        }

        // Print the raw equations
        System.out.println("Extracted Equations: " + extractedEquations);
        
        // Iterate through the raw equations to find variables
        for (String rawEquation : extractedEquations) {
        	List<String> variables = new LinkedList<String>(Arrays.asList(rawEquation.split("[,:]")));
            System.out.println("Equation pieces found " + variables.size());
            String equation = variables.remove(variables.size() - 1); // The last element in the list will be your equation
            
            System.out.println("The equation is: " + equation);
            
            // Iterate through the variables, split on '=' and find/replace in your equation
            for (String variable : variables) {
            	List<String> declaration = new LinkedList<String>(Arrays.asList(variable.split("=")));
                
                System.out.println("The variable " + declaration.get(0) + " is equal to " + declaration.get(1));
                
                
                // TODO you'll want to match whole variable names between operators as they could be partially matching and then replaced leaving you with an unusable or wrong equation. e.g. $$$var=1,var2=2:var+variable2$$$, if not handled properly would result in "1+1iable2" instead of "1+2"
                equation = equation.replaceAll(declaration.get(0), declaration.get(1));
            }
            
            System.out.println("The equation after replacing variables: " + equation);
        }
  }
}